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Do you need a permit for an accessory dwelling unit (ADU)?

Permits for ADUs are set locally: the city or county building department decides, under the code it has adopted. Below are the official rules and fees we verified, in each department's own words.

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On this page
  1. State laws on accessory dwelling units (ADUs)
  2. What cities charge for an accessory dwelling unit (ADU) permit
  3. Before you start
  4. Sources

State laws on accessory dwelling units (ADUs)

33 states in our records have a statute on this. Each entry quotes the statute; the state page has the rest.

Alaska

  • Boroughs provide land use regulation. (a) A first or second class borough shall provide for planning, platting, and land use regulation on an areawide basis.1
  • Local zoning by ordinance. …zoning regulations restricting the use of land and improvements by geographic districts…1

Arizona A.R.S. § 9-461.18 (cities and towns over 75,000); § 11-810.01 (counties); § 11-820.03 (park model trailers)

  • At least one attached and one detached accessory dwelling unit as a permitted use.2
  • A minimum of one additional detached accessory dwelling unit as a permitted use on a lot or parcel that is one acre or more in size if at least one accessory dwelling unit on the lot or parcel is a restricted-affordable dwelling unit.2
  • 1,000 square feet. An accessory dwelling unit that is seventy-five percent of the gross floor area of the single-family dwelling on the same lot or parcel or one thousand square feet, whichever is less.2
  • Require that a lot or parcel have additional parking to accommodate an accessory dwelling unit or require payment of fees instead of additional parking.2

Arkansas A.C.A. § 14-56-205 (Acts 2025, No. 313)

  • One ADU by right. Except as provided in this section, a municipality shall not adopt a policy, regulation, or ordinance that restricts, prohibits, or otherwise regulates the use of at least one (1) accessory dwelling unit by right on a lot or parcel that contains a single-family dwelling.5
  • ADU definition. "Accessory dwelling unit" means a self-contained and independently accessed living unit on the same parcel as a single-family dwelling of greater square footage that includes its own cooking, sleeping, and sanitation facilities and complies with or is otherwise exempt from any applicable regulatory requirements…5
  • Attached, detached or internal. An accessory dwelling unit may be attached, detached, or internal to the single-family dwelling on a lot or parcel.5
  • 1,000 square feet. If the accessory dwelling unit is detached from or attached to the single-family dwelling, it shall not be more than seventy-five percent (75%) of the gross floor area of the single-family dwelling or one thousand square feet (1,000 sq. ft.), whichever is less.5

California Cal. Gov. Code §§ 66310-66342

  • Ministerial, no hearing. A permit application for an accessory dwelling unit shall be considered and approved ministerially without discretionary review or a hearing, notwithstanding Section 65901 or 65906 or any local ordinance regulating the issuance of variances or special use permits.6
  • 15 business days. A permitting agency shall determine whether an application to create or serve an accessory dwelling unit is complete and provide written notice of this determination to the applicant not later than 15 business days after the permitting agency received the application.6
  • 60 days. The permitting agency shall either approve or deny the application to create or serve an accessory dwelling unit within 60 days from the date the permitting agency receives a completed application if there is an existing single-family or multifamily dwelling on the lot.6
  • Deemed approved after 60 days. If the local agency has not approved or denied the completed application within 60 days, the application shall be deemed approved.6

Enacted in California but not yet in effect:

  • Two detached new-construction ADUs allowed on a lot with a single-family home. Two detached, new construction, accessory dwelling units that do not exceed four-foot side and rear yard setbacks for a lot with a proposed or existing single-family dwelling.6 Stats. 2026, Ch. 791 (AB 956); in effect from 6
  • No junior ADU required on a lot where two detached new ADUs were built. Notwithstanding subdivision (a), a local agency is not required to ministerially approve an application for a building permit to create a junior accessory dwelling unit on the same lot where two detached, new construction, accessory dwelling units have been constructed pursuant to paragraph (2) of subdivision (a).6 Stats. 2026, Ch. 791 (AB 956); in effect from 6
  • For up to two ADUs on a lot, impact fees only on the area above 750 sq ft. (B) For up to two accessory dwelling units on a lot, any impact fees charged for an accessory dwelling unit that has more than 750 square feet of interior livable space shall be charged proportionately in relation to the square footage of the primary dwelling unit, and only on the area in excess of 750 square feet of interior livable space.6 Stats. 2026, Ch. 809 (SB 1117); in effect from 6

Colorado C.R.S. §§ 29-35-402 to 29-35-404 (HB 24-1152)

  • On or after June 30, 2025, a subject jurisdiction shall allow, subject to an administrative approval process, one accessory dwelling unit as an accessory use to a single-unit detached dwelling in any part of the subject jurisdiction where the jurisdiction allows single-unit detached dwellings.9
  • No new off-street parking, with exceptions. Require the construction of a new off-street parking space in connection with the construction or conversion of an accessory dwelling unit, except as described in subsections (3)(a) and (3)(b) of this section…9
  • No owner-occupancy requirement, with limited residency proof. Require an accessory dwelling unit, or any other dwelling on the same lot as an accessory dwelling unit, to be owner-occupied; except that a subject jurisdiction may require a property owner to demonstrate that the property owner resides on the parcel when an application is submitted…9
  • No restrictive design or dimension standard. Apply a restrictive design or dimension standard to an accessory dwelling unit.9

Connecticut Conn. Gen. Stat. § 8-2o, as amended by P.A. 26-7, § 2

  • …provided at least one accessory [apartment] dwelling unit shall be allowed as of right on each lot that contains a single-family dwelling and no such accessory [apartment] dwelling unit shall be required to be an affordable accessory [apartment] dwelling unit…10
  • Attached, internal or detached. Allow accessory [apartments] dwelling units to be attached to or located within the proposed or existing principal dwelling, or detached from the proposed or existing principal dwelling and located on the same lot as such dwelling…10
  • At least 30% of principal dwelling or 1,000 sq ft, whichever is less. Set a maximum net floor area for an accessory [apartment] dwelling unit of not less than thirty per cent of the net floor area of the principal dwelling, or one thousand square feet, whichever is less, except that such regulations may allow a larger net floor area for such [apartments] accessory dwelling units…10
  • 65 days. …that a decision on any such application be rendered not later than sixtyfive days after receipt of such application by the applicable zoning commission, except that an applicant may consent to one or more extensions of not more than an additional sixty-five days or may withdraw such application.10

Delaware 29 Del. C. §§ 9221-9222, added by 85 Del. Laws, c. 343 (SS 2 for SB 23)

  • Affordable housing plans must authorize ADUs without a conditional use permit or special exception. Authorization for a mix of housing types, including single-family detached, single-family attached, duplexes, triplexes, multifamily dwellings, accessory dwelling units, cottage housing developments, and manufactured housing without the need for a conditional use permit or special exception.13
  • Applies through local plans. A local jurisdiction that has a population greater than 2,000 and that is required to adopt a comprehensive plan under Title 9, Title 22, or this title must include an affordable housing plan consistent with this subchapter as part of its comprehensive plan.13
  • February 1, 2027 cutoff for a limited exemption. February 1, 2027 Cutoff for the limited exemption: jurisdictions adopting their next comprehensive plan before this date get until their following 5-year review to comply with § 9222 plan-content requirements.14

District of Columbia 11-U DCMR § 253

  • One accessory apartment in an R zone. One (1) accessory apartment may be established in an R zone, subject to the provisions of this section.15
  • Matter of right in principal dwelling or accessory building, except R-1B/GT and R-3/GT. An accessory apartment shall be permitted in a principal dwelling or an accessory building as a matter of right in the R zones, except the R-1B/GT or R 3/GT zone, subject to the provisions of this section.15
  • Owner-occupancy required. Either the principal dwelling or accessory apartment unit shall be owner-occupied for the duration of the accessory apartment use.15
  • Occupancy cap of 3 persons outside GT zones. The total number of persons that may occupy the accessory apartment shall not exceed three (3), except in the R-1B/GT or R-3/GT zone where the aggregate number of persons that may occupy the house, including the principal dwelling and the accessory apartment combined, shall not exceed six (6).15

Florida Fla. Stat. § 163.31771

  • Definition. (a) “Accessory dwelling unit” means an ancillary or secondary living unit, that has a separate kitchen, bathroom, and sleeping area, existing either within the same structure, or on the same lot, as the primary dwelling unit.16
  • Local option, not a mandate. (3) A local government may adopt an ordinance to allow accessory dwelling units in any area zoned for single-family residential use.16
  • Affordable-rent affidavit. (4) An application for a building permit to construct an accessory dwelling unit must include an affidavit from the applicant which attests that the unit will be rented at an affordable rate to an extremely-low-income, very-low-income, low-income, or moderate-income person or persons.16
  • Counts toward affordable housing. (5) Each accessory dwelling unit allowed by an ordinance adopted under this section shall apply toward satisfying the affordable housing component of the housing element in the local government’s comprehensive plan under s. 163.3177(6)(f).16

Georgia

  • HB 1166 (2026), 400 sq ft dwellings, bill only. HB 1166 Local government; zoning decisions shall not affect or be required for certain residential dwellings of 400 square feet or fewer; provide…17
  • HB 1166 session-final status row. 1166 County and municipal corporations; zoning procedures; provisions GAff H 2/4 2/26 S 2/5 3/6 3/6 CS SLGO(G) S 3/9 3/27 S 3/27…18

Hawaii HRS § 46-4.8 (Act 39, Session Laws of Hawaii 2024); HRS § 46-4(c)

  • Act 39 of 2024 requires county ordinances allowing additional units. WHEREAS, in 2024, the Legislature passed Senate Bill 3202, SD2, HD1, CD1, which Governor Josh Green signed into law as Act 39, Session Laws of Hawaii 2024 (“Act 39”), which required the four counties to enact ordinances to allow additional dwelling units on residentially zoned lots, to allow further subdivision of such lots, and to amend the calculation of impact fees for certain developments…19
  • At least two ADUs; county deadline December 31, 2026. Repeals Act 39, Session Laws of Hawaii 2024, which required the counties, no later than 12/31/2026, to adopt or amend an ordinance to allow at least two accessory dwelling units, subject to certain restrictions, on all residentially zoned lots.19
  • Separate older county option for two single-family units. Except as provided in section 46-4.8, each county may adopt reasonable standards to allow the construction of two single-family dwelling units on any lot where a residential dwelling unit is permitted.20

Idaho Idaho Code § 67-6541 and § 55-3212, as added and amended by 2026 S1354 as amended (Session Law ch. 265)

  • Cities must allow either one internal ADU or one detached ADU per lot on land zoned single-family. Allow for either one (1) internal accessory dwelling unit within the single-family dwelling or one (1) detached accessory dwelling unit per lot in the rear yard or subject to setbacks required of the primary dwelling…21
  • Cities may not require owner occupancy of the primary dwelling or the ADU. Prohibit an owner-occupancy requirement for the primary dwelling or for the accessory dwelling unit…21
  • Effective February 1, 2027. By February 1, 2027, by resolution or ordinance adopted, amended, or repealed in accordance with the notice and hearing procedures provided under section 67-6509, Idaho Code, each city governing board shall amend its comprehensive plan and land use regulations for all land zoned for single-family residential uses, except for lands falling within an area defined as a historic district under section 67-4607, Idaho Code, or designated as a historic property pursuant to section 67-4614, Idaho Code, to…21
  • No required off-street or guest parking, with stated exceptions. Prohibit requiring any off-street parking or guest parking for any accessory dwelling unit unless the principal dwelling unit does not have off-street parking or the street is not paved and designed or constructed for on-street parking or unless the principal dwelling unit is within one-fourth (1/4) mile of transit, an employment area, or commercial services…21

Indiana HEA 1001 (2026), reported IC 36-7-1-1.5 (unread)

  • Bill-stage: accessory dwelling unit within a single family dwelling as a permitted use. (2) An accessory dwelling unit within a single family dwelling.22
  • Bill-stage status as of February 17, 2026. Status as of 2/17: Passed House, referred to Senate Tax and Fiscal Policy committee…22
  • Bill-stage: automatic ADU approval unless opt out. Accessory dwelling units can be approved automatically, and local design standards and parking rules may be waived unless municipalities choose to opt out.23
  • February 2026 statement: no statewide ADU rule. There is no statewide rule, but many cities and rural areas have set clear guidelines for adding small homes on single-family lots.23

Iowa Iowa Code §§ 364.3(23), 331.301(29), as amended by 2026 Iowa Acts ch. 1013 (S.F. 2369); enacted by 2025 Iowa Acts ch. 38 (S.F. 592)

  • A city shall allow a minimum of one accessory dwelling unit on the same lot as a single family residence within a zoning district where a single family residence is an allowed principal use, in accordance with the following conditions…24
  • A county shall allow a minimum of one accessory dwelling unit on the same lot as a single family residence within a zoning district where a single family residence is an allowed principal use, in accordance with the following conditions…24
  • Must meet building regulations. An accessory dwelling unit shall comply with all applicable building regulations as defined in chapter 103A.24
  • 1,000 square feet. An accessory dwelling unit shall not exceed one thousand square feet or fifty percent of the size of the single family residence, whichever is larger.24

Kansas K.S.A. 12-776 (Supp.); 2026 Kan. Sess. Laws ch. 76 (SB 418) § 1

  • Accessory dwelling unit definition. (1) "Accessory dwelling unit" or "ADU" means a secondary housing unit that is subordinate to the primary dwelling unit on the same lot and may include a separate kitchen, bathroom and entrance.27
  • ADUs that meet the definition and local zoning criteria are approved by right. (1) All proposed housing developments, including single-family homes, townhouses and accessory dwelling units (ADUs), that meet the definition of a by-right housing development pursuant to subsection (b)(2) and the criteria outlined in the zoning code and land use regulations shall be approved by-right, without the need for discretionary review or approval by planning commissions, zoning boards or other regulatory bodies.27
  • 30 days. (2) A complete application for a by-right housing development that demonstrates that such development meets the criteria outlined in the zoning code and land use regulations shall be deemed approved unless the application is denied within 30 days of receipt by the permitting or regulatory authority, or within 60 days for an application that requires approval of a subdivision plat pursuant to K.S.A. 12-752, and amendments thereto, or within 90 days for an application that requires approval of a subdivision plat of more than 40 single-family homes pursuant to K.S.A. 12-752, and amendments thereto.27
  • Not by right in a national register district or under historic review. …are not located within a district listed on the national register of historic places or otherwise subject to historic preservation review under applicable state, federal or local law.27

Louisiana

  • ADU defined in the state code rule, and must follow the code. Accessory Dwelling units shall be designed and constructed in accordance with the Louisiana State Uniform Construction Code.29

Maine 30-A M.R.S. §4364-B; 25 M.R.S. §2463-B

  • ADU must be allowed where residential uses are permitted. Except as provided in Title 12, chapter 423‑A, a municipality shall allow an accessory dwelling unit to be located on the same lot as a single-family dwelling unit or 2-unit or 3-unit residential structure in any area in which residential uses are permitted, including as a conditional use, in accordance with this section.30
  • Interior, attached or new structure. As a new structure on the lot for the primary purpose of creating an accessory dwelling unit.30
  • At least one per qualifying lot. At least one accessory dwelling unit must be allowed on any lot where the principal structure is a single-family dwelling unit or 2-unit or 3-unit residential structure…30
  • Density exemption. A municipality shall exempt one accessory dwelling unit on a lot from any density requirements or calculations related to the area in which the accessory dwelling unit is constructed.30

Maryland Md. Code, Land Use §§ 4-501 to 4-504; Real Property §§ 2-126, 11B-111.11 (Chapter 196 of 2025)

  • Each legislative body must adopt a local ADU law by October 1, 2026. (1) On or before October 1, 2026, each legislative body shall adopt a local law authorizing the development of accessory dwelling units in accordance with this section.35
  • 75%. …not greater than 75% of the size of and subordinate in use to the primary single–family detached dwelling unit.35
  • ADU may be separate or an attached addition. …separate from the primary single–family detached dwelling unit…35
  • Must meet building codes and adequate public facilities provisions. (b) A local law adopted under this section shall provide for construction of accessory dwelling units that meet public health, safety, and welfare standards, including relevant building codes and adequate public facilities provisions.35

Massachusetts M.G.L. c. 40A, § 3; 760 CMR 71.00; St. 2024, c. 150, § 8

  • By-right single ADU in single-family districts. St. 2024, c. 150, § 8 establishes that in certain circumstances the use of land or structures for ADUs are protected from zoning restrictions by providing that zoning shall not prohibit, unreasonably restrict or require a special permit or other discretionary zoning approval for the use of land or structures for a single ADU, or the rental thereof, in a single-family residential zoning district, and imposes protections on ADUs through M.G.L. c. 40A, § 3, the Dover Amendment.37
  • No owner occupancy requirement. St. 2024, c. 150, § 8, however, explicitly prohibits municipalities from imposing requirements on protected accessory dwelling unitsthat require owner-occupancy of either the ADU or the principal dwelling and imposes limitations on Municipal parking requirements.37
  • Size limit. …is not larger in Gross Floor Area than ½ the Gross Floor Area of the Principal Dwelling or 900 square feet, whichever is smaller…37
  • Only one protected ADU per lot. …provided that only one ADU on a lot may qualify as a Protected Use ADU.37

Minnesota

  • 300 square feet. …be no more than 300 gross square feet…39
  • Local accessory-use rules cannot bar a qualifying temporary dwelling. A temporary family health care dwelling that meets the requirements of this section cannot be prohibited by a local ordinance that regulates accessory uses or recreational vehicle parking or storage.39
  • 6 months. The initial temporary dwelling permit is valid for six months.39
  • City may opt out. A municipality may by ordinance opt-out of the requirements of this section.39

Montana Mont. Code Ann. §§ 76-2-345 (municipal), 76-2-215 (county)

  • At least one ADU by right in municipal zoning. A municipality shall adopt regulations under this chapter that allow a minimum of one accessory dwelling unit by right on a lot or parcel that contains a single-family dwelling.40
  • Attached, detached or internal. An accessory dwelling unit may be attached, detached, or internal to the single-family dwelling on a lot or parcel.40
  • 1,000 square feet. If the accessory dwelling unit is detached from or attached to the single-family dwelling, it may not be more than 75% of the gross floor area of the single-family dwelling or 1,000 square feet, whichever is less.40
  • No required added parking. …require that a lot or parcel have additional parking to accommodate an accessory dwelling unit or require fees in lieu of additional parking…40

Nebraska Municipal Density and Missing Middle Housing Act

  • Act requires biennial housing reports from larger cities. Under the Municipal Density and Missing Middle Housing Act, metropolitan, primary and first class cities with a population of at least 20,000 are required to submit biennial reports to the committee.43
  • Veto override failed. An attempt to override the veto failed on a vote of 19-28.43

Nevada NRS 278.257 (added by 2025 Nev. Stat. 2376, AB 396)

  • Large counties and cities must adopt ADU ordinances. 1. Except as otherwise provided in this section, each governing body of a county whose population is 100,000 or more and each governing body of a city whose population is 60,000 or more shall adopt an ordinance that authorizes the development and use of an accessory dwelling unit on residential property.44
  • Ordinance cannot prohibit separate kitchen facilities. (a) Prohibit separate kitchen facilities for the accessory dwelling unit.44
  • Ordinance cannot require more than one extra parking space, if existing and street parking meet the need. (b) Require more than one additional parking space for the accessory dwelling unit provided that the existing parking for the primary residence and street parking satisfy the anticipated parking needs for the accessory dwelling unit.44
  • Ordinance cannot require a side or rear setback more restrictive than for the primary residence. (c) Require any side or rear setback for the accessory dwelling unit that is more restrictive than the requirements for the primary residence.44

New Hampshire RSA 674:71 to 674:73

  • One ADU by right, attached or detached. One accessory dwelling unit, which may be either attached or detached, shall be allowed as a matter of right.46
  • 950 square feet. The total living space of the accessory dwelling unit shall not exceed 950 square feet unless otherwise authorized by the municipality.46
  • 750 square feet. A municipality may not restrict the total living space to less than 750 square feet.46
  • Owner occupancy may be required. A municipality may require owner occupancy of one of the dwelling units, but it shall not specify which unit the owner must occupy.46

New Jersey

  • IRC ADU appendix not adopted. Deleted in their entirety: AA, Board of Appeals; AB, Permit Fees; AC, Reserved; BA, Manufactured Housing Used as Dwellings; BC, Accessory Dwelling Units (ADU); BD…47

New Mexico

  • 2026 HB 17 would have required ADUs in home rule municipalities. House Bill 17 amends New Mexico's zoning laws by removing "morals" as a basis for zoning restrictions, eliminating the term "multigenerational," and requiring home rule municipalities to allow accessory dwelling units (ADUs) and multifamily housing in designated areas.48
  • HB 17 is not on the governor 2026 signed list. 2026 Signed Legislation…49
  • Current zoning statute still says "morals". For the purpose of promoting health, safety, morals or the general welfare, a zoning authority may regulate and restrict within its jurisdiction the…50

Oregon ORS 197A.425; ORS 215.495

  • Cities over 2,500 and counties over 15,000 must allow at least one ADU per detached single-unit dwelling inside the UGB. (1)(a) A city with a population greater than 2,500 or a county with a population greater than 15,000 shall allow in areas within the urban growth boundary that are zoned for detached single-unit dwellings the development of at least one accessory dwelling unit for each detached single-unit dwelling, subject to reasonable local regulations relating to siting and design.51
  • ADU may be interior, attached or detached. (A) “Accessory dwelling unit” means an interior, attached or detached residential structure that is used in connection with or that is accessory to a single-unit dwelling.51
  • No owner-occupancy or extra off-street parking requirements. (B) “Reasonable local regulations relating to siting and design” does not include owner-occupancy requirements of either the primary or accessory structure or requirements to construct additional off-street parking.51
  • Vacation occupancies may still be regulated. (2) Subsection (1) of this section does not prohibit local governments from regulating vacation occupancies, as defined in ORS 90.100, to require owner-occupancy or off-street parking.51

Rhode Island R.I. Gen. Laws §§ 45-24-31, 45-24-37, 45-24-73

  • Providence: one ADU per residentially zoned lot (city zoning guidance). One ADU is permitted per residentially zoned lot.52

South Carolina

  • H. 3469 would create a property tax exemption for certain ADUs (bill only). "ACCESSORY DWELLING UNIT AFFORDABLE HOUSING INCENTIVE ACT" BY AMENDING SECTION 12-37-220, RELATING TO PROPERTY TAX EXEMPTIONS, SO AS TO PROVIDE A PROPERTY TAX EXEMPTION FOR CERTAIN ACCESSORY DWELLING UNITS.53
  • IRC Appendix BB Tiny Houses adopted statewide (2024 cycle). Appendix BB is adopted for statewide use.54

Utah Utah Code §§ 10-21-101, 10-21-303, 10-21-304 (municipalities); § 17-80-303 (counties); IRC amendments in § 15A-3-202

  • Internal ADU is a permitted use in residential zones. …the use of an internal accessory dwelling unit is a permitted use…55
  • Internal ADU defined (within footprint, long-term rental). …within the footprint of the primary dwelling described in Subsection (16)(a) at the time the internal accessory dwelling unit is created; and (c) for the purpose of offering a long-term rental of 30 consecutive days or longer.56
  • Internal ADU must meet building, health and fire codes. (2) An internal accessory dwelling unit shall comply with all applicable building, health, and fire codes.55
  • 6,000 square feet. …prohibit the creation of an internal accessory dwelling unit if the lot containing the primary dwelling is 6,000 square feet or less in size…55

Vermont 24 V.S.A. § 4412(1)(E)-(F); 20 V.S.A. § 2730(b)(4)

  • One ADU per owner-occupied single-family lot is a permitted use. (E) Except for flood hazard and fluvial erosion area bylaws adopted pursuant to section 4424 of this title, no bylaw shall have the effect of excluding as a permitted use one accessory dwelling unit that is located within or appurtenant to a single-family dwelling on an owner-occupied lot.59
  • Same review as a single-family dwelling without an ADU. A bylaw shall require a single-family dwelling with an accessory dwelling unit to be subject to the same review, dimensional, or other controls as required for a single-family dwelling without an accessory dwelling unit.59
  • Conversion of detached nonresidential building no stricter than for a single-family dwelling. The criteria for conversion of an existing detached nonresidential building to habitable space for an accessory dwelling unit shall not be more restrictive than the criteria used for a single-family dwelling without an accessory dwelling unit.59
  • Local bylaws may be less restrictive; short-term rentals may be regulated separately. (F) Nothing in subdivision (1)(E) of this section shall be construed to prohibit: (i) a bylaw that is less restrictive of accessory dwelling units; or (ii) a bylaw that regulates short-term rental units distinctly from residential rental units.59

Washington RCW 36.70A.680, 36.70A.681, 36.70A.696

  • Cities and counties planning under the GMA must adopt ADU rules by their next periodic plan update. (1)(a) Cities and counties planning under this chapter must adopt or amend by ordinance, and incorporate into their development regulations, zoning regulations, and other official controls the requirements of this section and of RCW 36.70A.681, to take effect at the same time as the jurisdiction's next periodic comprehensive plan update required under RCW 36.70A.130.63
  • State rules preempt conflicting local rules where a jurisdiction has not adopted. (b) In any city or county that has not adopted or amended ordinances, regulations, or other official controls as required under this section, the requirements of this section and RCW 36.70A.681 supersede, preempt, and invalidate any conflicting local development regulations.63
  • Only inside urban growth areas. (2) Ordinances, development regulations, and other official controls adopted or amended pursuant to this section and RCW 36.70A.681 must only apply in the portions of towns, cities, and counties that are within urban growth areas designated under this chapter.63
  • The city or county must allow at least two accessory dwelling units on all lots that are located in all zoning districts within an urban growth area that allow for single-family homes in the following configurations…63

West Virginia W. Va. Code §§8-42-1 to 8-42-3 (2026 SB 659, Acts 2026 ch. 241)

  • Municipalities must allow at least one ADU by right on a lot with a single-family dwelling. (a) Except as provided in this article, a municipality shall not adopt a policy, regulation, or ordinance that restricts, prohibits, or otherwise regulates the use of at least one accessory dwelling unit by right on a lot or parcel that contains a single-family dwelling.64
  • Attached, detached or internal. (b) An accessory dwelling unit may be attached, detached, or internal to the single-family dwelling on a lot or parcel.64
  • 1,000 square feet. (c) If the accessory dwelling unit is detached from or attached to the single-family dwelling, it shall not be more than 75 percent of the gross floor area of the single-family dwelling or 1,000 square feet, whichever is less.64
  • No additional parking may be required. Require that a lot or parcel have additional parking to accommodate an accessory dwelling unit or require fees in lieu of additional parking…64

Virginia enacted, not yet in effect

  • ADU is a permitted accessory use in single-family zoning districts. B. Zoning ordinances for single-family residential zoning districts shall be deemed to include accessory dwelling units as a permitted accessory use, and no locality shall require compliance with any other requirements except as provided in this section.68 Va. Code § 15.2-2292.4; in effect from
  • Definition: attached or detached unit with complete independent living facilities on same lot. As used in this section, "accessory dwelling unit" or "ADU" means an attached or detached dwelling unit on a residential dwelling lot that: [...] 1. Provides complete independent living facilities for one or more individuals; [...] 2. Is located on the same lot as a proposed or existing primary residence…68 Va. Code § 15.2-2292.4; in effect from
  • $500. C. Any person proposing an ADU shall first obtain an ADU permit from the locality, for which the locality may charge a fee of no more than $500.68 Va. Code § 15.2-2292.4; in effect from
  • ADU permit fee is in addition to building permit fees. Such fee shall be in addition to any other applicable fees, including inspection, site, or building permit fees, that may be required in connection with the ADU.68 Va. Code § 15.2-2292.4; in effect from
  • Localities may require 30-day minimum lease. A lease term for the rental of an ADU of 30 consecutive days or longer…68 Va. Code § 15.2-2292.4; in effect from
  • Size limits may not be set below 350 sq ft (lots < 2,500 sq ft) or 500 sq ft (larger lots). Limits on floor area, lot coverage, and impervious area of an ADU of no less than (i) 350 square feet on lots less than 2,500 square feet and (ii) 500 square feet on lots 2,500 square feet or greater…68 Va. Code § 15.2-2292.4; in effect from
  • Building code compliance may be required. Compliance with (i) building codes, including the requirements of the Uniform Statewide Building Code (§ 36-97 et seq.), for an accessory dwelling unit if the ADU is attached or for a dwelling unit if the ADU is detached; (ii) water, sewer, septic, emergency access, flood zone, and stormwater requirements; (iii) historic and architectural districts and corridor protection restrictions; and (iv) Air Installations Compatible Use Zone restrictions…68 Va. Code § 15.2-2292.4; in effect from
  • Owner occupancy of ADU or primary dwelling may be required only at application. Owner occupancy of the ADU or the primary dwelling, but not both, only at the time an application is submitted to construct or convert an accessory dwelling unit…68 Va. Code § 15.2-2292.4; in effect from
  • Setback cap. Rear or side setbacks for the ADU that are greater than the setback required for the primary dwelling or the setback required for accessory structures on the residential lot, whichever is less…68 Va. Code § 15.2-2292.4; in effect from
  • HOA/condo covenants not overridden. F. Nothing in this section shall be construed to supersede or limit contracts or agreements between or among individuals or private entities related to the use of real property, including recorded declarations and covenants, the provisions of condominium instruments of a condominium created pursuant to the Virginia Condominium Act (§ 55.1-1900 et seq.), the declaration of a common interest community as defined in § 54.1-2345, the cooperative instruments of a cooperative created pursuant to the Virginia Real Estate Cooperative Act (§ 55.1-2100 et seq.), or any declaration of a property owners' association created pursuant to the Property Owners' Association Act (§ 55.1-1800 et seq.).68 Va. Code § 15.2-2292.4; in effect from
  • Localities with an ADU ordinance adopted before January 1, 2026 are excluded. I. Nothing in this section shall apply to a locality that adopted an ADU ordinance prior to January 1, 2026.68 Va. Code § 15.2-2292.4; in effect from

What cities charge for an accessory dwelling unit (ADU) permit

Fee lines as each city’s schedule states them, never added up into a total; how permit fees work explains valuation formulas and minimums.

CityFeeAs the schedule states it
New York City, NYNew building work permit: One-, two- or three-family dwelling (no existing elements retained)$0.06 for each square foot, or fraction thereof, of the total floor area of the new building, but not less than $130 for each structure.69
Los Angeles, CACombined building-mechanical permit (one- or two-family dwelling, accessory buildings, ADUs)As determined by Table 1-A.170
San Diego, CARes-SDU/DUP Add/Remodel (Table 501A)Plan check $3,512.92 base (1 sq ft) / $3,512.92 + $6.98 increment (500 sq ft base); inspection $2,228.29 / $2,228.29 + $4.4671
Jacksonville, FLNew buildings, accessory buildings and additions - BID permit fee per 100 sq ft enclosed area (up to 4th story)Building Inspection Division (BID) permit fee · $6.3872
Charlotte, NCCity of Charlotte - Residential Single-Family Reviews - Individual Residential Lot Review (zoning)$15573
Nashville, TNBuilding Permit Fees for Residential Construction (one- and two-family, townhouses)1. Building Permit Fees for Residential Construction based on valuation. Residential construction includes one-family and two-family residential construction and townhouses as defined by the 2018 Edition of the International Residential Code, but not multi-family construction shall be $5.00 per $1,000 total valuation.74
Nashville, TNPlans examination fee: exceptions (one- and two-family dwellings)2. Exceptions from plans examination fee: a. One- and two-family dwelling building permits;74
El Paso, TXBuilding Permit - Residential: additions or new single family residential construction 401-1299 sq ft$0.87 per square foot plus applicable Technology Fee75
El Paso, TXBuilding Permit - Residential: additions or new single family residential construction 1300-2399 sq ft$0.82 per square foot plus applicable Technology Fee75
Boston, MALong Form Building$50.00 Primary fee plus $10.00 per $1,000.00 of the estimated cost of work.76
Baltimore, MDNew buildings and additions, 1- and 2-family dwellings1. 1- and 2-family dwellings $10 for each 1,000 cubic feet (28.31 cu. m.) or fraction of 1,000 cubic feet (28.31 cu. m.) of gross volume, including all basements and cellars. Minimums – New building $150 Additions $7577
Tucson, AZBuilding Permit Fees for New Construction: $1 to $2,000Base fee $89.45 + $0.00 per additional $1,000 (valuation tier 1–2000)78
Tucson, AZBuilding Permit Fees for New Construction: $2,000.01 to $25,000Base fee $89.45 + $22.95 per additional $1,000 (valuation tier 2000.01–25000)78
Tucson, AZBuilding Permit Fees for New Construction: $25,000.01 to $50,000Base fee $617.30 + $16.83 per additional $1,000 (valuation tier 25000.01–50000)78
Mesa, AZResidential Rate Table - Building Permit Fee (BPF) for Valuations of: $0 to$0 to $8,333 $220.0079
Mesa, AZResidential Rate Table - Building Permit Fee (BPF) for Valuations of: $8,334 to$8,334 to $16,667 $330.0079
Mesa, AZResidential Rate Table - Building Permit Fee (BPF) for Valuations of: $16,668 to$16,668 to $24,999 $440.0079
Raleigh, NCNew Residential Building PermitNew Residential Construction Building Permit Fee 0.35% 0.38% % Of Calculated Construction Value80
Raleigh, NCZoning Permit Fee - 1&2 Family Dwellings Existing StructuresA Zoning Permit is required for residential development activity. $253.00 $261.00 Per Review80
Colorado Springs, COTable A building permit fee (row $1 to $500)$1 to $500 $50.0081
Colorado Springs, COTable A building permit fee (row $501 to)$501 to $2,000 $50.00 for the first $500 plus $2.00 for each additional $100 or fraction thereof, to and including $2,00081
Colorado Springs, COTable A building permit fee (row $2,001 to)$2,001 to $25,000 $80.00 for the first $2,000 plus $8.00 for each additional $1,000 or fraction thereof, to and including $25,00081
Miami, FLEnergy Conservation Surcharge, New Construction or Addition per square footi. Energy Conservation Surcharge New Construction or Addition per square foot $0.1182
Virginia Beach, VAResidential living area (heated), new and additions$50.00 plus $7.00 per 100 square feet of area or fraction thereof83
Long Beach, CACombination Building Permit (Group R-3 / U-1)150% of Building Permit fee per permit, but not less than $17084
Oakland, CAResidential Building - New Construction - R3 - Plan Review1. Residential Building - New Construction - R3 - Plan Review · 10.6085
Oakland, CAResidential Building - New Construction - R3 - Inspection2. Residential Building - New Construction - R3 - Inspection · 8.0085
Aurora, CONew building fee, R-3 single family homes (per sq ft, minimum)R-3* Single Family Homes $1.30 $2,00086
Aurora, COCapital Impact Fee, single-family detachedSingle-family (detached) · $9,327 per unit87
Austin, TXBuilding Base Fee (Single Family, Duplex, Townhouse, and Other Residential Structure Fees)$318.4888

Before you start

Find your city’s accessory dwelling unit (ADU) rule with the permit checker. What to check before you buy materials (city limits, limits in the rule, zoning and HOA rules) and the order of the steps are in how to get a building permit; what an exemption does not cover is in work exempt from a permit.

Sources

  1. AS 29.40 Planning, Platting, and Land UseAlaska State Legislature (BASIS), Alaska StatutesChecked November 5, 2026
  2. 9-461.18 - Accessory dwelling units; regulation; applicability; definitionsArizona State Legislature, Arizona Revised StatutesChecked November 5, 2026
  3. 11-810.01 - Accessory dwelling units; regulation; applicability; definitionsArizona State Legislature, Arizona Revised StatutesChecked November 5, 2026
  4. 11-820.03 - Accessory dwelling unit; park model trailer; definitionsArizona State Legislature, Arizona Revised StatutesChecked November 5, 2026
  5. Act 313 of the Regular Session (HB1503), 2025Arkansas General AssemblyAdopted March 18, 2025Checked November 5, 2026
  6. Government Code Section 66317California Legislature, Legislative Information (leginfo) public data downloadEffective January 1, 2026Checked November 7, 2026
  7. Accessory Dwelling UnitsCalifornia Department of Housing and Community DevelopmentChecked November 5, 2026
  8. Accessory Dwelling Unit Handbook, March 2026California Department of Housing and Community DevelopmentPublished March 2026Checked November 5, 2026
  9. C.R.S. Title 29, Article 35, Part 4 (accessory dwelling units), selected sectionsColorado General Assembly (Colorado Revised Statutes 2024, published on the legislature's site)Published 2024Checked November 5, 2026
  10. Public Act No. 26-7, An Act Concerning Utility Connections for Accessory Dwelling UnitsState of Connecticut, General Assembly (Public Acts)Adopted May 7, 2026Checked November 5, 2026
  11. Bill History, Session Year 2026, Substitute for Raised H.B. No. 5288State of Connecticut, General Assembly (bill status)Checked November 5, 2026
  12. Bill History, Session Year 2026, Substitute for Raised H.B. No. 5507State of Connecticut, General Assembly (bill status)Checked November 5, 2026
  13. 29 Del. C. ch. 92, subch. III, Affordable Housing ActState of Delaware, Delaware Code OnlineChecked November 7, 2026
  14. Initial Implementation Guidance: Delaware's 2026 Land Use & Housing ReformsState of Delaware, Office of State Planning CoordinationPublished September 25, 2026Checked November 5, 2026
  15. 11-U DCMR § 253 Accessory Apartment (R)District of Columbia, Office of Documents and Administrative Issuances (D.C. Municipal Regulations)Effective August 25, 2023Checked November 5, 2026
  16. Fla. Stat. § 163.31771 (2026 Florida Statutes)State of Florida, The Florida Senate (Florida Statutes)Published 2026Checked November 5, 2026
  17. House General Calendar, March 4, 2026Georgia General Assembly, House of RepresentativesPublished March 4, 2026Checked November 5, 2026
  18. Georgia State Senate 2026 Composite Status, Session FinalGeorgia General Assembly, Georgia State SenatePublished May 14, 2026Checked November 5, 2026
  19. Resolution 25-271City and County of Honolulu, City CouncilAdopted October 1, 2025Checked November 5, 2026
  20. HRS 46-4State of Hawaii, Hawaii Revised Statutes (Legislature)Checked November 5, 2026
  21. 2026 Senate Bill 1354, As AmendedState of Idaho, Idaho LegislatureChecked November 5, 2026
  22. Plan Commission Minutes, February 18, 2026Town of Porter, IndianaPublished February 18, 2026Checked November 5, 2026
  23. Land Use & Housing Update, Economy & Place CommitteeNorthwestern Indiana Regional Planning CommissionPublished February 11, 2026Checked November 7, 2026
  24. 2026 Iowa Acts chapter 1013 (S.F. 2369), Accessory Dwelling UnitsIowa General Assembly, Acts and Joint ResolutionsAdopted April 9, 2026Checked November 6, 2026
  25. Iowa Code section 364.3Iowa General Assembly, Iowa Code 2026Published 2026Checked November 7, 2026
  26. 2025 Iowa Acts chapter 38 (S.F. 592), Accessory Dwelling UnitsIowa General Assembly, Acts and Joint ResolutionsAdopted May 1, 2025Checked November 6, 2026
  27. 2026 Senate Bill No. 418 (enrolled), by-right housing development actKansas LegislatureAdopted April 7, 2026Checked November 7, 2026
  28. SB 418 bill historyKansas LegislaturePosted April 9, 2026Checked November 5, 2026
  29. Building Code Adoption & Inspector Licensing Law and Rules and RegulationsState of Louisiana, Louisiana Uniform Construction Code CommissionPublished August 1, 2026Checked November 7, 2026
  30. Title 30-A, §4364-B: Accessory dwelling unitsMaine Legislature, Office of the Revisor of StatutesLast updated October 5, 2026Checked November 5, 2026
  31. Title 25, §2463-B: Fire protection in accessory dwelling unitsMaine Legislature, Office of the Revisor of StatutesLast updated October 5, 2026Checked November 5, 2026
  32. P.L. 2025, c. 733 (H.P. 1461, L.D. 2173), An Act to Update the Laws Regarding Housing Developments and Accessory…Maine LegislatureAdopted April 16, 2026Checked November 5, 2026
  33. Title 30-A, §4364: Affordable housing densityMaine Legislature, Office of the Revisor of StatutesLast updated October 5, 2026Checked November 5, 2026
  34. Housing Legislation Guidance, March 2026Maine Office of Community AffairsPublished March 2026Checked November 5, 2026
  35. Md. Code, Land Use § 4-504Maryland General Assembly, Annotated Code of MarylandChecked November 5, 2026
  36. House Bill 1538, 2026 Regular SessionMaryland General AssemblyChecked November 5, 2026
  37. 760 CMR 71.00: Protected Use Accessory Dwelling UnitsCommonwealth of Massachusetts, Executive Office of Housing and Livable CommunitiesPublished January 31, 2025Checked November 6, 2026
  38. Building & ZoningCity of Worcester, Inspectional Services, Building & ZoningChecked November 6, 2026
  39. Minn. Stat. § 462.3593 Temporary family health care dwellingsMinnesota Office of the Revisor of Statutes, Minnesota StatutesPublished 2026Checked November 5, 2026
  40. Mont. Code Ann. § 76-2-345Montana Legislature, Legislative Services Division, Montana Code AnnotatedPublished 2025Checked November 6, 2026
  41. Mont. Code Ann. § 76-2-215Montana Legislature, Legislative Services Division, Montana Code AnnotatedPublished 2025Checked November 6, 2026
  42. SB 532 (2025), Ch. 619, L. 2025 enrolled billMontana LegislaturePublished 2025Checked November 6, 2026
  43. Session Review: Urban Affairs (2026)Nebraska Legislature, Unicameral UpdatePosted May 15, 2026Checked November 6, 2026
  44. NRS Chapter 278 - Planning and ZoningNevada Legislature, Legislative Counsel Bureau (Nevada Revised Statutes)Checked November 7, 2026
  45. Zoning Code Clean-UpCity of RenoChecked November 6, 2026
  46. RSA Chapter 674: Local Land Use Planning and Regulatory PowersNew Hampshire General Court, RSAChecked November 5, 2026
  47. N.J.A.C. 5:23-3, SubcodesNJ Department of Community Affairs (Administrative Code copy)Last updated August 17, 2026Checked November 6, 2026
  48. 2026 Legislative Summary of Housing Bill and FundingNew Mexico Mortgage Finance Authority (Housing New Mexico)Published February 12, 2026Checked November 6, 2026
  49. Signed LegislationOffice of the Governor of New MexicoChecked November 6, 2026
  50. Chapter 3, Article 21 NMSA 1978, Zoning RegulationsNew Mexico Compilation Commission, NMOneSource (NMSA 1978 Unannotated)Last updated November 4, 2026Checked November 6, 2026
  51. Chapter 197A — Land Use Planning (ORS)Oregon State Legislature, Oregon Revised StatutesChecked November 6, 2026
  52. ADU Types and Guidelines for the City of Providence (as of October 2025)City of Providence, Department of Inspection + StandardsPublished October 2025Checked November 6, 2026
  53. 2025-2026 Bill 3469: Accessory Dwelling Unit Affordable Housing Incentive ActSouth Carolina General AssemblyLast updated February 5, 2025Checked November 6, 2026
  54. South Carolina State Register Vol. 50, Issue 5: Final Regulations, Building Codes Council Docs 5416-5418, 5424,…South Carolina General Assembly, Legislative Council (State Register)Published May 22, 2026Checked November 6, 2026
  55. Utah Code 10-21-303, Internal accessory dwelling unitsState of Utah, Utah State Legislature (Utah Code)Effective November 6, 2025Checked November 7, 2026
  56. Utah Code 10-21-101, Definitions (Municipalities and Housing Supply)State of Utah, Utah State Legislature (Utah Code)Effective July 1, 2026Checked November 6, 2026
  57. Utah Code 10-21-304, Detached accessory dwelling unitsState of Utah, Utah State Legislature (Utah Code)Effective October 1, 2026Checked November 6, 2026
  58. Utah Code 15A-3-202, Amendments to Chapters 1 through 5 of IRCState of Utah, Utah State Legislature (Utah Code)Effective July 1, 2026Checked November 6, 2026
  59. 24 V.S.A. § 4412. Required provisions and prohibited effectsVermont General Assembly, Vermont Statutes OnlineChecked November 6, 2026
  60. 20 V.S.A. chapter 173: Prevention and Investigation of FiresVermont General Assembly, Vermont Statutes OnlineChecked November 6, 2026
  61. Vermont Fire & Building Safety Code 2025Vermont Department of Public Safety, Division of Fire Safety (rule PDF)Effective November 4, 2025Checked November 7, 2026
  62. Vermont Electrical Safety Rules 2025Vermont Electricians' Licensing Board and Department of Public Safety, Division of Fire Safety (rule PDF)Effective November 5, 2025Checked November 7, 2026
  63. RCW 36.70A.680Washington State Legislature, Revised Code of WashingtonChecked November 6, 2026
  64. W. Va. Code §8-42-2 Prohibition on policy regulations restricting accessory dwelling unitsWest Virginia LegislatureChecked November 6, 2026
  65. W. Va. Code §8-42-3 Exemptions (Accessory Dwelling Units)West Virginia LegislatureChecked November 6, 2026
  66. W. Va. Code §8-42-1 Definitions (Accessory Dwelling Units)West Virginia LegislatureChecked November 6, 2026
  67. Senate Bill 659, 2026 Regular Session, Bill StatusWest Virginia LegislatureEffective June 4, 2026Checked November 6, 2026
  68. § 15.2-2292.4. (Effective July 1, 2027) Development and use of accessory dwelling unitsCommonwealth of Virginia, Division of Legislative Automated Systems (Virginia Law, Code of Virginia)Effective July 1, 2027Checked November 6, 2026
  69. 2022 NYC Construction Codes, General Administrative Provisions (Admin. Code Title 28), Chapter 1 AdministrationCity of New York, Department of BuildingsChecked November 7, 2026
  70. SEC. 91.107. FEES. (LAMC Ch. IX, Art. 1, Div. 1)City of Los Angeles (Los Angeles Municipal Code, hosted by American Legal Publishing)Checked November 6, 2026
  71. Information Bulletin 501: Fee Schedule for Construction Permits-StructuresCity of San Diego, Development Services DepartmentRevised August 2026Checked November 7, 2026
  72. City Fees (Categorized by Departments)City of Jacksonville, City Fees page (Building Inspection Division - Section 320.409)Checked November 7, 2026
  73. FY27 Residential Zoning Fees (PDF)City of Charlotte, CLT Development Center (Planning, Design & Development)Effective July 1, 2026Checked November 7, 2026
  74. Codes Fee Schedule (Building-Permit-Fee-Scheudle-2025.pdf)Metropolitan Government of Nashville and Davidson County, Department of Codes and Building SafetyPosted December 2025Checked November 7, 2026
  75. City of El Paso FY2026-2027 Adopted Budget, FY 2027 Schedule C Departmental Fee ListCity of El Paso, Office of Management & BudgetAdopted August 18, 2026Checked November 7, 2026
  76. Building Fees 5 15 23 (ISD fee schedule)City of Boston, Inspectional Services DepartmentChecked November 7, 2026
  77. Section 109. Fees (Building Code)City of Baltimore Law Library (Department of Legislative Reference)Checked November 7, 2026
  78. Planning and Permitting Fee Schedule (Adopted Year 1 Fee Schedule, FY27)City of Tucson, Planning & Development Services Department (PDSD)Effective July 1, 2026Checked November 7, 2026
  79. Schedule of Fees and Charges - Development ServicesCity of Mesa, Development Services DepartmentRevised July 2026Checked November 7, 2026
  80. Development Fee Guide July 1, 2026 - June 30, 2027City of Raleigh, Planning and DevelopmentEffective July 1, 2026Checked November 7, 2026
  81. Fee Schedule - Pikes Peak Regional Building Department (Appendix B: Fee Schedule, 2023 PPRBC)Pikes Peak Regional Building Department (PPRBD)Effective June 30, 2025Checked November 7, 2026
  82. Exhibit C Fee Schedule, Building, Chapters 10, 17, 20 (File No. 19087, Exhibit C Sub)City of Miami (City Commission Resolution R-26-0200), Building Department fee scheduleAdopted April 23, 2026Checked November 7, 2026
  83. Residential Building Permit FeesCity of Virginia Beach, Planning & Community Development, Permits & Inspections DivisionRevised July 2025Checked November 7, 2026
  84. Building Plan Review & Permit FeesCity of Long Beach, Community Development Department, Building and Safety BureauEffective October 1, 2026Checked November 7, 2026
  85. Fiscal Year 2026-27 Master Fee ScheduleCity of Oakland (Master Fee Schedule, Planning & Building Department section)Effective July 1, 2026Checked November 7, 2026
  86. Fee Schedule 3 - Permit and Plan Review Fees (Effective 2026)City of Aurora, Development Services DepartmentEffective 2026Checked November 7, 2026
  87. Development Fees Checklist - City of AuroraCity of Aurora, Development CenterEffective 2026Checked November 7, 2026
  88. City of Austin Fee Schedule | Residential Building Plan Review & Inspection Permit FeesCity of Austin, Austin Development ServicesEffective October 1, 2026Checked November 7, 2026